There is disclosed in U.S. Pat. No. 5,158,481, a shielded electrical connector comprising; a terminal support block, contact terminals supported on the block for connection to wires, and shielding for the connector comprising; a mating end on a front shell encircling a mating end of the terminal support block, conductive backshells enveloping the block, and a deformable strain relief on the backshells.
The backshells close together similarly as do mating halves of a clamshell, and fit one within another. The front shell is fabricated as a seamless drawn tube with an exact profile to conform to the shape of a mating electrical connector. The profile must be free of distortion, especially as distortion may occur when a strain relief on the shielding is subject to deformation to grip an electrical cable. The front shell, being a separate drawn part, is isolated from the deformable strain relief on the backshells.
The front shell requires a somewhat elaborate connection to the backshells, described as follows. The backshells and front shell are assembled by hooks passing through slots in the front shell. Compression beams near the hooks press against the front shell to establish electrical continuity between the front shell and the backshells.
In such a connector as described in U.S. Pat. No. 3,760,335, care must be taken to prevent shifting of the terminal support block, accompanied by the contact terminals, relative to the front shell, especially while the connector undergoes mating connection with another, mating electrical connector. During mating connection, the contact terminals of the mating connectors engage and wipe against one another, advantageously cleaning the terminals of oxides and other contaminants that would cause an undesired voltage drop across the surfaces of the contact terminals. Shifting of the terminal block during the course of mating connection decreases the stroke of contact wiping that advantageously cleans the contact terminals.